python动态导入模块、检查模块是否安装
参考链接：http://www.woodpecker.org.cn/diveintopython/functional_programming/dynamic_import.html
一 动态导入模块
Python的import不能接受变量，所以应该用 __import__函数来动态导入。
如下的代码无法正常导入模块
modules = ['OpenSSL', 'Crypto', 'MySQLdb', 'sqlite3', 'zope.interface', 'pyasn1', 'twisted', 'django']
for each in modules:
try:
import each
except Exception, e:
print e
这样导入会抛出 No module named each
的异常
将 import each 改为 __import__(each)就可以正常导入了。
二 检查模块是否安装
使用__import__函数也可以用来检查模块是否已安装，略微修改上面的代码即可。
使用imp.find_module()来检查不方面，如find_module('zope.interface')会抛出异常——因为这个函数无法查找子模块。
模块加载后，就可以在sys.module这个字典里找到加载的模块名了。
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And last here is the overload operators example:
# map() takes two (or more) arguments, a function and a list to apply the function to
# lambda can be put anywhere a function is expected
# map() calls lambada for every element in the self list
# since Vector has overloaded __getitem__ and __len_ ......
#shell排序
def ShellPass(mylist, d):
size = len(mylist)
i = d
while i < size:
if mylist[i] < mylist[i - d]:
tmp = mylist[i]
j = i - d
mylist[j + d] = mylist[j]
j = j - d
while j >= 0 and mylist[j] > ......
#堆排序
def Heapify(mylist, start, end):
left = 0
right = 0
maxv = 0
left = start * 2
right = start * 2 + 1
while left <= end:
maxv = left
if right <= end:
if mylist[left] < mylist[right]:
maxv = right
......
def MergeSort(mylist, low, mid, high):
i = low
j = mid + 1
tmp = []
while i <= mid and j <= high:
if mylist[i] <= mylist[j]:
tmp.append(mylist[i])
i = i + 1
else:
tmp.append(mylist[j])
j = j + 1
......
#!/usr/bin/env python
#coding=utf-8
def buildConnectionString(params):
return ":".join(["%s=%s" %(k, v) for k, v in params.items()])
if __name__ == "__main__":
myParams = {"server":"mpilgrim", \
&nbs ......
